Editor’s note: Since April 15, 2013, Running Times has received many reflections from runners around the world in the aftermath of the tragedy at the Boston Marathon. We are grateful for your stories. We thought this one, by Michael Cassidy, who was featured in RT the May, 2013, issue, captured the essence and spirit of many.

I’m also an American. I’m a Catholic. I’m a New Yorker. I’m a graduate student. I’m a former government employee.

Those things describe me. But running defines me.

I am a runner who ran the 2013 Boston Marathon. My family and I — like most runners — were fortunate to be out of harm’s way. The victims were someone else’s child, someone else’s parent, someone else’s friend. Their faces and names were unfamiliar, their pain incomprehensible.

But they were part of the tribe of runners, family and friends of runners. They are the type of people who sacrifice Friday nights for Saturday mornings — or support it. The type of people who measure life in minutes per mile — or can interpret it. The type of people whose most treasured possession stinks up the closet — or at least don’t complain about it. They are strangers, but they are runners, and so we know who they are.

Runners share an unspoken bond, a spiritual affinity that runs deeper than age or race, nationality or religion. Show me a runner, and I’ll show you a friend. Running identifies.

Running is not something you do; it is something you are. It’s a worldview as much as it is a form of exercise. It’s a way of life as much as it is a sport. It’s a state of being as much as it is a means of transportation. An attack on any of us running is an attack on all of us.

That is why we must run on.

The cruelest part of the bombings was the jarring juxtaposition between the senseless slaughter of innocents and the marathon’s jubilant pageantry. In an instant, something we had spent months and years meticulously preparing for became magnificently inconsequential. Our standard obsessions — in my case, a disappointing finishing time — suddenly seemed astoundingly selfish.

The overriding sentiment was one of shocked disbelief, tinged with anxious outrage. A sacred ritual had been gruesomely desecrated. We were confused, angry, scared. We wanted comfort, security, revenge. But most of all, we wanted answers.

Who did this? How could this happen? Will marathons change forever?

In the wake of tragedy it is natural to ask questions. To change perspectives. To challenge priorities.

As runners, we were forced to confront a troubling truth: Running was fallible, even trivial. As we watched others suffer, we were forced to ask: Does running matter?

And the reality is: Running doesn’t matter as much as we think. It matters more.

When despair is overwhelming, what do we do? Go for a run. When stress is oppressive, what do we do? Go for a run. When hope is gone and all seems lost, what do we do? Go for a run.

A run can turn the worst day into the best day; it can bring us from the lowest of lows to the highest of highs. I ran after September 11, I ran after the deaths of my grandparents, and I run whenever things aren’t going my way. It never fails.

If the perpetrators wanted to inflict lasting devastation, they could not have picked a worse target. Running defies destruction.

To run is to live. Running nourishes our muscles and nurtures our minds. It induces clarity of thought, vitality of physiology, and tranquility of emotion. It demands complete unity of body and spirit, it requires your legs, your lungs, your heart, your mind, but rewards all those parts too. It’s in this harmonious holism that we come to understand our true identities, our authentic selves. The universe’s uncertainty is distilled into a singularity: We exist in and of the moment. In the midst of entropy, serene bliss. In the midst of confusion, clarity. Surrounded by constraints, we are freed. Running creates.

But running is more than the antithesis of terror; it is also the antidote. Just as a vaccine implicates pestilence in its own defense, running takes pain as a template and produces something beautiful.

Terror holds no more power over running than wind over wildfire. Runners do not avoid suffering, they embrace it. Pain is merely the pathway to our potential. From the depths of agony rise meaning and purpose.

It is perhaps this fact that separates runners from non-runners, and it’s why we are the subject of curious bemusement and occasional derision. In a world that celebrates leisure and luxury, runners seek austerity. In a world in search of simple answers, runners chase impossible questions. In a society that valorizes the easy way, runners take the path of most resistance.

But it goes deeper than that. We do it together. Running unites.

The falsest truism in all of sports is that running is an individual pursuit. Anyone who has ever run for a team recognizes the value of training partners. They push us when we’re hurting. They make us laugh when we want to scream. They turn our doubts into confidence, our dreams into realities. United by shared sacrifice, they become lasting friends.

But the same is true of our opponents. In running, there is no such thing as foes, only co-conspirators. It’s one of the few competitive endeavors where my success doesn’t mean your failure.

Sure, only one person can win — but it’s not a zero-sum game. The real rewards are diffuse and self-defined. Victory and defeat — these occur internally, in our ability to conquer our emotions and triumph over our own limitations. Work together, and we realize collective greatness. Our fates are linked. It’s no accident that records are often set in pairs. As much as relative success yields medals, as much as podiums mean prize money, as much as second place is a footnote, we cannot hide from our most relentless rival: ourselves.

And this amicable accord extends beyond the athletes to the fans. In running, the sidelines are part of the playing field. If competitors require us to run faster, crowds inspire it. Nothing can galvanize greatness as much as throngs of screaming fans. Running persists on passion. It rides on emotion. Cheers can’t compensate for underprepared hearts or untrained legs, but they can make those hearts beat a little faster and those legs drive a little harder.

Just as important as the volume is the attitude: inclusive rather than exclusive, universal rather than partisan. In running, cheering for someone doesn’t mean rooting against someone else. Being a fan at a marathon is an expression of genuine altruism: helping a stranger without request or recompense.

Kind words infuse failing spirits with optimism. Internal anguish is transformed into external glory. I’ve always felt a marathon felt seems shorter when it’s 26.2 miles of compliments. Adrenaline is a heck of a drug.

Nowhere is this more obvious than Boston, where the fans are unquestionably the most passionate, most knowledgeable spectators in our sport (and this is coming from a Yankee fan). In many cities, a marathon is a significant event; in Boston, it is a holiday. Lined with fans, Heartbreak Hill feels flatter. With applause echoing, the Citgo sign approaches faster. When you do something for 117 years, you get pretty good.

It’s days like the Boston Marathon that remind us the running community is greater than the sum of its parts. Bound by the pursuit of the same ephemeral euphoria, our collective presence makes its realization all the more likely.

This is why running community must carry on — not in spite of Boston, but because of it.

As we heal from the attacks, the right question to ask is not if we should run, but why we run.

It’s not about running logs or mile splits, PRs or age-group awards, breaking tapes or setting records. It’s much more basic than that. We run because it’s who we are.

Running cannot resurrect lives or repair limbs, but it can recall the spirit that brings us together on Marathon Monday. It reminds us that even on the loneliest of long runs, we are not alone. We are part of something bigger. What distinguishes running is not solitariness, but solidarity.

Each run is an emphatic statement for everything that terrorism is not. Terrorism destroys; running creates. Terrorism divides; running unites. Terrorism is about fear; running is about hope. Terrorism signifies giving up; running means pushing ahead. Terrorism represents humankind at its malevolent worst; running, people at their inspirational best.

When we run, we take a stand for life, and in so doing, we bring into being the very spirit that defines the greatest threat to terrorism: the unconditional embrace of existence, the relentless optimism that progress is possible, and the unflinching conviction that our individual hopes are inseparable from our shared humanity.

To transcend our limits, we must confront our own mortality. As runners, reaching new levels demands staring human fragility in the face, accepting the futility of our quest, and forging ahead anyway.

Then somehow, when those magic Marathon Mondays come, what was once unfathomable becomes unavoidable. The inconceivable becomes tractable; the hypothetical, real. The most insurmountable peak becomes a mere plateau on the path to greater heights. The boundary is extended. The cycle begins anew. The finish line becomes the starting line.